edu.isi.stella
Class MemoizableIterator

java.lang.Object
  edu.isi.stella.Stella_Object
      edu.isi.stella.StandardObject
          edu.isi.stella.AbstractIterator
              edu.isi.stella.Iterator
                  edu.isi.stella.MemoizableIterator

public class MemoizableIterator
extends Iterator

Iterator class with value buffering that can be used to memoize some baseIterator without having to generate all its values first. The memoized iterator needs to be cloned to allow multiple iterations over the collection represented by the memoized iterator. Use the following idiom to memoize some arbitrary iterator and return a properly cloned value: (clone-memoized-iterator (memoize (...) <options>* (new MEMOIZABLE-ITERATOR :base-iterator <base-iterator>))) This will ensure that <base-iterator> is exhausted exactly once even if there are multiple clones for the same memoized value, and that each value is generated as late as absolutely possible. THIS IS NOT YET THREAD SAFE!

Field Summary

Iterator	baseIterator This slot is only needed to pass the base iterator to the constructor.
Cons	cursor Trailing cursor to the list of values generated so far.
Cons	iteratorAndValues Holds the base iterator and the values generated so far.

Fields inherited from class edu.isi.stella.Iterator

value

Fields inherited from class edu.isi.stella.AbstractIterator

firstIterationP

Constructor Summary

MemoizableIterator()

Method Summary

static Stella_Object	accessMemoizableIteratorSlotValue(MemoizableIterator self, Symbol slotname, Stella_Object value, boolean setvalueP)
AbstractIterator	allocateIterator() Alias for cloneMemoizedIterator.
static Iterator	cloneMemoizedIterator(MemoizableIterator self) Clone the memoized iterator self so it can be used to iterate over the collection represented by self, while allowing to iterate over it multiple times via multiple clones.
void	initializeMemoizableIterator()
static MemoizableIterator	newMemoizableIterator(Iterator baseIterator)
boolean	nextP() Generate the next value of the memoized iterator self (or one of its clones) by either using one of the values generated so far or by generating and saving the next value of the baseIterator.
Surrogate	primaryType() Returns the primary type of self.

Methods inherited from class edu.isi.stella.Iterator

advance, concatenate, consify, emptyP, listify, memberP, pop, printClassList

Methods inherited from class edu.isi.stella.AbstractIterator

accessAbstractIteratorSlotValue, length

Methods inherited from class edu.isi.stella.StandardObject

arrayTypeSpecifierP, baseTypeToTypeSpec, cantOverwriteActiveCollectionSlot, compatibleParameterTypesP, computeAnchoredTypeSpec, computeRelativeTypeSpec, conformingTypeSpecP, copyWrappedLiteral, cppReferenceTypeP, cppReferencizeType, cppTranslateAndPointerizeTypeSpec, cppTranslateAndReferencizeTypeSpec, cppTranslateTypeSpec, dropSlotValue, extractParameterType, extractRequiredArgumentValues, getSlot, hashCode_, idlTranslateTypeSpec, inverseSlotDemon, javaLiteralP, javaNativeLiteralWrapperNames, javaSpecialSetterName, javaTranslateArrayOfTypeSpec, javaTranslateTypeSpec, javaTranslateTypeSpecForFunction, javaTranslateTypeSpecHelper, javaYieldClassObjectArrayExpression, javaYieldClassObjectExpression, javaYieldFullyQualifiedTypeName, javaYieldTranslatedClassAndMethodNames, listifyTypeSpec, lookupClTypeFromStellaType, objectEqlP, putSlotValue, readSlotValue, runConstructorDemons, runDestructorDemons, runSlotDemons, runSlotGuardDemonsP, standardObjectP, subTypeSpecOfP, twoArgumentLeastCommonSupertype, typeSpecToBaseType, typeSpecToClass, typeToWalkedNullValueTree, validateTypeSpecifier, voidP, walkTypeSpecIsNativeTypeP, writeSlotValue, yieldTypeSpecTree

Methods inherited from class edu.isi.stella.Stella_Object

_, accessInContext, amPm, anchoredTypeSpecifierP, andOrNotTreeP, applyCoercionMethod, atomicExpressionP, bindToSurrogateP, booleanP, bootstrapIsaP, bquotify, cast, characterP, clTranslateAtomicTree, clTranslateATree, clTranslateBooleanTest, clTranslatePlainBooleanTest, clTranslateVerbatimBodySymbols, clYieldTypedExpressionTree, coerceATree, coerceEvaluatedTree, coerceMvTree, coerceToBoolean, coerceToModule, coerceToModuleName, coerceToSymbol, coerceToXmlElement, coercibleP, collectFeatureList, collectKeyValueList, commonLispSymbolP, computeExpressionType, cons, consifyListsAndIterators, consP, consTreeMatchP, convertToLiteral, copyConsTree, cppArgumentIsStreamP, cppBinaryOperatorP, cppBlockP, cppMaybeOutputStatementWithParentheses, cppOperatorP, cppOutputAtomicExpression, cppOutputLiteral, cppOutputOneActualParameter, cppOutputStatement, cppOutputTypedEntity, cppPrognifyStatement, cppPrognP, cppStatementToList, cppStreamIsStandardOutputP, cpptrans, cppTranslateAtomicTree, cppTranslateATree, cppTranslatedArrayTypeP, csValueP, dateDivider, dateTimeDivider, day, dealWithAmPm, dealWithEra, dealWithNoonMidn, decrementReferenceCount, defaultOptionHandler, defineSystem, defmodule, deletedP, describe, describeObject, describeTersely, destructureMethodNameTree, deUglifyParseTree, either, eqlP, eqlToBooleanP, eqlToCharacterP, eqlToFloatP, eqlToIntegerP, eqlToStringP, equalConsTreesP, equalHashCode, equalP, era, estimatedEvaluationCost, evaluate, evaluateArgumentTree, evaluateAtomicTree, evaluateCommand, expandBquoteTree, filterModuleP, floatP, free, get, getObject, hashlist, hashMemoizedArguments, helpBquotify, helpClTranslateATree, helpCoerceATree, helpLptrans, helpPrintOutline, helpTransformBooleanProceduralExpression, helpWalkATree, homeModule, hour, idlOutputAtomicExpression, idlOutputLiteral, idlOutputStatement, idlTranslateAtomicTree, idlTranslateATree, illegalTreeP, implodePathname, incrementallyTranslate, incrementReferenceCount, inlineUnwrapBoolean, inlineWrapBoolean, inModule, integerP, isaP, javaBinaryOperatorP, javaBlockP, javaEndOfLineTokenP, javaHelpOutputPrintStream, javaMaybeOutputStatementWithParentheses, javaOperatorP, javaOutputLiteral, javaOutputStatement, javaPrognP, javaStreamIsStandardOutputP, javaSymbolCaseP, javaTranslateAtomicTree, javaTranslateATree, javaTranslateWithNativeWrapper, jptrans, keywordP, kvCons, legalTokenizerFromStateP, legalTokenizerStateP, legalTokenizerToStateP, literalEqlP, logLevelLE, lptrans, makeFileNameFromRelativePath, makeMemoizedValueEntry, makeMemoizedValueEntryn, matchConsTree, methodSlotP, minute, month, nameToString, nilP, noonMidn, numberWrapperToFloat, objectEqualP, objectHashCode, one, oneI, onlyIf, parametricTypeSpecifierP, parseArrayDimensionsSpec, parseTokenizerCharacterSpec, parseTokenizerStateModifiers, permanentCopy, permanentify, permanentifyForm, po, prettyPrintLiteral, primaryClass, printObject, printOutline, printStellaCode, printStellaDefinition, printUndefinedSuperClasses, proceduralExpressionP, ptrans, publicSlots, registerRecycledItem, runOptionHandlerP, safeEqualHashCode, safeHashCode, safePrimaryType, safeYieldTypeSpecifier, searchConsTreeP, searchConsTreeWithFilterP, searchForObject, secondp, sideEffectFreeExpressionP, simplifyBquoteTree, specialp, stella_Increment, stellaClassP, stellaCollectionP, stellaNeedToCompileP, stellaNeedToTranslateP, stellaObjectP, stellify, storageSlotP, stringifyInModule, stringP, substituteConsTree, substituteOnce, surrogateP, surrogatify, sweep, symbolCaseP, symbolP, sysTree, targetLanguageType, taxonomyIsaP, timeDivider, timeMultiply, tokenizerIncludeSpecP, tokenizerToStateAlias, tokenizerToStateName, toString, traceIf, traceKeywordP, transientifyForm, transientObjectP, transientSymbolP, translateWalkedTree, treeSize, treeToTrees, trueOptionP, tryToEvaluate, typeP, typify, unmake, unregisterRecycledItem, updateInContext, valuesTreeP, variableExpressionP, verbatimStringP, verbatimTreeP, vetOptions, vrletExpressionP, walkAtomicTree, walkATree, walkCollectionTree, walkDontCallMeTree, walkedExpressionType, walkExpressionTree, walkMvExpressionTree, walkMvTree, walkStatement, walkTopLevelExpression, walkWithoutTypeTree, warnAboutUnknownSourceType, weekday, withinContext, withinModule, withinWorld, withStellaTokenizer, withSystemDefinition, withTokenizer, wrapperP, wrapWhereTest, xmlAttributeP, xmlCdataFormP, xmlCdataP, xmlDeclarationFormP, xmlDeclarationP, xmlDoctypeFormP, xmlElementFormP, xmlElementP, xmlnsAttributeP, xmlProcessingInstructionFormP, xmlProcessingInstructionP, xmlTagCase, year, yieldCondTest, yieldCondTestOrTests, yieldHardcodedCaseSymbolIdOrIds, yieldInCursorClausesForArgumentList, yieldInCursorClausesForGeneralCollection, yieldInCursorClausesForVector, yieldTypeSpecifier, zone, zoneMinute

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

baseIterator

public Iterator baseIterator

This slot is only needed to pass the base iterator to the constructor. Once self is initialized it will be cleared.

iteratorAndValues

public Cons iteratorAndValues

Holds the base iterator and the values generated so far. This slot is structure shared between the memoized iterator and all its clones to make sure everybody sees any new values generated by any one of the clones, and that everybody can see when the base iterator is exhausted.

cursor

public Cons cursor

Trailing cursor to the list of values generated so far. Once the end of the list is reached this slot is used to add new values to the end of iteratorAndValues.

Constructor Detail

MemoizableIterator

public MemoizableIterator()

Method Detail

newMemoizableIterator

public static MemoizableIterator newMemoizableIterator(Iterator baseIterator)

nextP

public boolean nextP()

Generate the next value of the memoized iterator self (or one of its clones) by either using one of the values generated so far or by generating and saving the next value of the baseIterator.

Overrides:

nextP in class AbstractIterator

Returns:

boolean

allocateIterator

public AbstractIterator allocateIterator()

Alias for cloneMemoizedIterator.

Overrides:

allocateIterator in class AbstractIterator

Returns:

AbstractIterator

cloneMemoizedIterator

public static Iterator cloneMemoizedIterator(MemoizableIterator self)

Clone the memoized iterator self so it can be used to iterate over the collection represented by self, while allowing to iterate over it multiple times via multiple clones.

Parameters:

self -

Returns:

Iterator

initializeMemoizableIterator

public void initializeMemoizableIterator()

accessMemoizableIteratorSlotValue

public static Stella_Object accessMemoizableIteratorSlotValue(MemoizableIterator self,
                                                              Symbol slotname,
                                                              Stella_Object value,
                                                              boolean setvalueP)

primaryType

public Surrogate primaryType()

Description copied from class: Stella_Object

Returns the primary type of self. Gets defined automatically for every non-abstract subclass of OBJECT.

Overrides:

primaryType in class Stella_Object

Returns:

Surrogate